Malaria and Ivermectin

Malaria is a mosquito-borne infection that affects more than 200 million people worldwide. The disease is transmitted when an infected mosquito bites an individual, spreading a parasite called plasmodium. In humans, the parasite can cause fever, headache, chills and even death. Malaria-carrying mosquitoes are increasingly becoming resistant to the insecticides meant to wipe them out.

Suppose, for once, we start thinking creatively. Suppose we humans could take a medicine that wouldn't kill the parasite, but one that is able to kill those pesky malaria-carrying mosquitoes if they feed on human blood. Well, such a medicine already exists and it is called ivermectin.

Ivermectin was developed in the early 1980s as a drug to fight parasites that cause river blindness and elephantiasis. Scientists now hope it can also help eradicate malaria.

One study has shown that, after a cure of just seven days, Ivermectin at a dose of 600 μg/kg was able to reduce mosquito survival for at least 28 days after treatment. Ivermectin at a dose of 300 μg/kg per day for three days provided a good balance between efficacy and tolerability[1].

"The most exciting result was the fact that even one month after [the subjects took] ivermectin, their blood was still killing mosquitoes," lead-author Menno Smit says. "That's much longer than we thought."

Even at sub-lethal concentrations, Ivermectin is significantly slowing locomotor activity of mosquitoes, resulting in decreased feeding of human blood[2].

[1] Smit et al: Safety and mosquitocidal efficacy of high-dose ivermectin when co-administered with dihydroartemisinin-piperaquine in Kenyan adults with uncomplicated malaria (IVERMAL): a randomised, double-blind, placebo-controlled trial in The Lancet Infectious Diseases – 2018
[2] Sampaio et al: What does not kill it makes it weaker: effects of sub-lethal concentrations of ivermectin on the locomotor activity of Anopheles aquasalis in Parasites and Vectors - 2017